Related Experiment Video
Updated: Aug 7, 2026
09:27
Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways
Published on: June 24, 2016
The archaeal twin-arginine translocation pathway
1Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
Biochemical Society Transactions
|May 30, 2003
Summary
The twin-arginine translocation (Tat) pathway exports folded proteins. In Halobacterium sp. NRC-1, this system handles most secreted proteins, unlike other Archaea, adapting to high-salinity environments.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- The twin-arginine translocation (Tat) pathway uniquely exports fully folded proteins across membranes.
- Key components include TatA, TatB, and TatC, essential for Tat-dependent protein export.
- This pathway is present in Archaea, typically exporting a limited number of proteins, often cofactor-binding ones like iron-sulfur clusters and molybdopterin.
Purpose of the Study:
- To investigate the role and characteristics of the Tat pathway in Archaea.
- To highlight the unique Tat system found in the halophilic archaeon Halobacterium sp. NRC-1.
- To understand the adaptation of the Tat pathway in extreme environments.
Main Methods:
- Bioinformatic analysis of predicted Tat-dependent substrates in various archaeal species.
- Comparative analysis of Tat pathway components and substrate profiles across archaea.
- Examination of the Halobacterium sp. NRC-1 genome for Tat pathway substrate predictions.
Main Results:
- Most archaeal Tat pathways function similarly to bacteria, exporting a small subset of folded proteins.
- Halobacterium sp. NRC-1 exhibits an expanded Tat pathway system.
- The majority of extracellular proteins in Halobacterium sp. NRC-1 are predicted to be Tat substrates.
Conclusions:
- The Tat pathway's role in Archaea is generally conserved, facilitating the export of specific folded proteins.
- Halobacterium sp. NRC-1's Tat system is highly adapted, likely due to its halophilic lifestyle.
- This organism presents a unique model for studying Tat pathway evolution and function in extreme conditions.
More Related Videos
11:12Determination of the Optimal Chromosomal Location(s) for a DNA Element in Escherichia coli Using a Novel Transposon-mediated Approach
Published on: September 11, 2017
12:25Isolation of Physiologically Active Thylakoids and Their Use in Energy-Dependent Protein Transport Assays
Published on: September 28, 2018
Related Concept Videos
01:20Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
01:45Tail-anchoring of Proteins in the ER Membrane
Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
01:32Export of Misfolded Proteins out of the ER
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
01:22Protein Transport to the Thylakoids
Thylakoids are membrane-bound sac-like structures within the chloroplast that serve as sites for photosynthesis. Thylakoid lumen contains many electron transport proteins and is enclosed by a thylakoid membrane rich in the light-harvesting complex. Proteins targeted to the thylakoids are transported as precursors and are sorted by the general TOC/TIC import pathway. Once the precursor reaches the stroma, stromal processing peptidases remove their transit signal and expose thylakoid signal...
01:22Inorganic Nitrogen Assimilation
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme nitrate reductase...
01:26Bacterial Translocation and Protein Secretion
Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...